This invention concerns axial flow rotary separators of the type used to separate threshed material in combine harvesters and more particularly separators in which rotors with tined or finger-like elements are used to propel material circumferentially within a cylindrical casing while helical guide elements provide at least a part of the required axial indexing effect.
In separator rotors using tines or finger-like elements it is already known to provide some form of yielding or pivoting of the element with respect to the rotor frame. Hall et al. for example, in U.S. patent application Ser. No. 646,346 now U.S. Pat. No. 4,611,605, discloses finger elements pivoted about an axis perpendicular to the rotor axis so that the fingers, while in engagement with a crop material mat, spiraling downstream under the influence of helical guide vanes, may move pivotably downstream with the mat so that the flow of the mat is not impeded. Schlayer in U.S. Pat. Nos. 1,688,662; 1,744,334 and 1,744,336 suggests yieldability of crop engaging elements in a plane perpendicular to the rotor axis but not pivoting or yielding in the direction taught by Hall. Schlayer (in '334) also teaches twisting the radially outward tips of the crop engaging elements so as to "feed the material in the direction towards the discharge end. Such feeding action is caused by the current of air produced by the helical form and also by the threshing members acting on the material in angular direction."
Use of the radially outward tip of the crop engaging element of the rotor to assist in axial propulsion is also disclosed in U.S. Pat. No. 723,670 Hixson in which the tip of a basically radially extending rod is bent into a generally axial but somewhat helical alignment so as to assist in axial propulsion while at the same time passing close enough to a separating grate portion of the casing, to assist in wiping material over the grate.
Each of the known crop material engaging element arrangements, by themselves or in combination with the particular separator casings and other components with which they are associated, operate moderately successfully but leave room for improvement.